The present invention relates to a method of depositing adhesives or adhesion control agents. More particularly, the present invention relates to a method of depositing adhesives or adhesive control agents that does not require contact with the surface upon which the material is being deposited.
Several techniques exist for the application of adhesives, most of which require direct contact between the surface receiving the adhesive and an applicator. Typically, automated applicators are used in order to facilitate current automated manufacturing processes. In many cases a special applicator must be designed and built for a particular manufacturing process. Most automated application processes are messy because the location of the adhesive cannot be accurately controlled.
The conventional adhesive application systems that have attempted to provide for accurate application of adhesives are slow and expensive. For example, in the greeting card industry there are special purpose cards produced with cut-outs, fold-outs, pop-ups, etc. The manufacturing of these cards requires that adhesives be applied in precise locations. However, the relatively limited manufacturing run of a single unique card makes many automated solutions too expensive. Furthermore, the typical contact type applicator does not work well when the adhesive needs to be applied to a very sensitive part, or to a material that is fuzzy or which might otherwise contaminate the applicator. In this situation the disadvantages of the traditional applicator are readily apparent.
Thus, there is a need for a fast and accurate deposition of adhesive in a no contact manner, at a low cost, and with easily modified amount and location, making it well suited for automated manufacturing.
There are also problems associated with the controlled deposition of adhesion control agents in a manufacturing environment. For example, consider the case of safety and security glasses. Security glasses are generally formed from two tempered glass plates that are autoclaved to adhere to a sheet of plastic located between the glass plates or sheets. The impact and shatter resistance of the resulting laminate depends greatly on the optimal control of the adhesion of the plastic sheet to the tempered glass. Too high or too low of a degree of adhesion of the sheet will decrease the impact and shatter resistance of the security glass. Precise and even distribution of an adhesion control agent on the surface of the plastic sheeting can result in optimal performance of the security glasses.
Gravure printing of the adhesion control agents has been considered. However, Gravure printing is capital intensive and prone to contamination.
Thus, there remains a need for an inexpensive method of depositing adhesion control agents that also reduces the likelihood of contamination.
The present invention allows for the fast and accurate deposition of adhesives in a no contact manner with one or more of the advantages of a low cost, an easily modified amount and location, making it well suited for automated manufacturing.
A method of manufacturing an assembled paper product is provided according to the present invention. The method includes the steps of providing a material to be formed into the product and providing an adhesive application device including an ink jet printing head and a reservoir containing adhesive. The method further includes depositing an adhesive onto a surface of a first portion of the material using the ink jet printing. The product is formed by bonding a second portion of the material to the first portion of the material using the adhesive deposited onto the first portion of the material. The position of the inkjet print head relative to the surface of material may be changed to deposit the adhesive in a desired location.
The adhesive may be deposited using a piezo-electric crystal to separate the adhesive into drops. Alternatively, the adhesive may be deposited using a thermal ink jet. In yet another alternative, the adhesive may be deposited using a continuous ink jet. Regardless of the type of ink jet used, the amount and thickness of the adhesive being deposited may be precisely controlled. The adhesive may be deposited in a line or other geometric shape depending on the particular card being constructed. The adhesive reservoir may be contained in a replaceable cartridge and the viscosity of the adhesive may be adjusted prior to depositing the adhesive.
According to an alternative embodiment of the present invention, a method of manufacturing safety glass is provided. The method includes the steps of providing a first and second sheet of glass and distributing an adhesion control agent onto a plastic sheet using an ink jet printing head. The method further includes positioning the sheet of plastic between the first and second sheets of glass and bonding the first and second sheets of glass to the sheet of plastic. The ink jet printing head may employ either thermal, continuous or piezo-electric ink jet printing methods.
Preferably, the step of bonding includes placing the glass and plastic sheets into an autoclave. The method also includes distributing the adhesion control agent uniformly over the plastic sheet. The plastic sheet may be formed by extrusion, and the adhesion control agent may be distributed after the plastic sheet exits an extrusion device. Either the plastic sheet or the ink jet print head may be moved in order to deposit the adhesion control agents as required on the plastic sheet. The control agents may be deposited on both sides of the sheet.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.